1
2
3
100

Nerve cells, or _______ are found in the ______ system.

neurons, nervous
100

A pair of skeletal muscles work together when one muscle _____ the other relaxes 

Contracts

100

Your spinal cord is part of the _________ system.

Central nervous

200

The process or breaking down food into a form that cells can use is called 

Digestion

200

Once air enters the body it moves to the ______ to the _____ and next to the _________.

Pharynx, trachea, bronchial tubes.

200

Tell how skeletal, cardiac, and, smooth muscles differ.

............

300

The tree kinds of muscles are

cardiac

skeletal

smooth

300

The esophagus and small intestine are parts of the _____ system.

digestive

300

Explain how the respiratory and circulatory systems provide oxygen and get rid of carbon dioxide.

............

400

______ muscles are voluntary

skeletal

400

Viruses are much ____ than bacteria

Smaller

400

Describe the path blood through the body.

...........

500

The _________ system protects your organs and helps you move

skeletal

500

Messages are sent to different body systems by the ______

Brain